Local inventor and innovator Bob Hockaday will be demonstrating the world's smallest and most affordable hydrogen fuel-cell car at 11 a.m. Saturday at Otowi Station Bookstore and Science Museum Shop.

Why a toy and not a full-sized car?

"Toys are the least threatening way to introduce a new technology," Hockaday said. "Many past technologies first were incorporated into toys before they were incorporated into 'serious' products. Fuel cells designed for cars and homes are not yet mature enough to make a good economic proposition to consumers yet."

Hockaday will demonstrate two cars.

"The first is part of a science kit," he said. "The hydrogen oxygen car has a transparent frame, fuel, motors, oxygen tanks, and fuel cell, so it is easy to see what is going on. Kids can make their own body covers.

"The second car is called the H-racer, and it has a sleek outer cover. The science kit fuel-cell car has a bump-and-roll drive system, so it bumps into barriers and turns. The H-racer is a straight-line drag racer. The H-racer is appropriate for ages 8 and above, and the fuel cell car science kit is for 12 and above."

The customer assembles the cars. The fuel cell itself is preassembled. Two AA batteries, human power/generator, or sunlight/photovoltaics provide the hydrogen fuel for the cars.

Hockaday said hydrogen combustion is occurring with all hydrocarbon combustion, from gasoline in automobile engines to natural gas furnaces.

"Hydrogen can burn over wider concentration ratios with air," he said, "and it will easily ignite with sparks. This ease of creating a reaction is also the reason it is a good fuel for fuel cells. There are applications and situations in which hydrogen is safer than gasoline or propane because hydrogen vapors rise and diffuse quickly, while gasoline and propane vapors flow along the ground and into depressions."

When using hydrogen fuel is not safer, Hockaday said, he would replace the gasoline, propane and natural gas with something like methanol or ethanol.

"In these cases, the alcohol fuel would be a safer energy carrier of the hydrogen and could be made from renewable sources," he said.

Toys aren't the only applications for hydrogen fuel cells.

"I see little tiny fuel cell power supplies for electronics that can run on minuscule amounts of fuel to cells that power cars and homes," Hockaday said. "Some of the unique features are that fuel cells could be used to store excess electrical energy and deliver it back on demand."

Although personal, portable fuel-cell products are feasible, obstacles remain.

"The fuel cell runs on a fuel supply," Hockaday said. "One of the commercialization hurdles is getting a socially acceptable fuel available to consumers. So along with the fuel cell comes the need to create a fueling infrastructure. A clever idea is to try and adapt to existing distribution of fuels such as alcohols."

He said that while hydrogen-powered automobiles are currently available, "the big question is affordability. The fuel cells right now are expensive. About a factor of at least 10 times too much to be competitive. If we go with a hybrid system with a small fuel cell running continuously, I think we could see cost competitive fuel cell/hybrid cars in about 5-10 years."

The advantages of using hydrogen fuel cells, Hockaday concluded, are that "they are quiet, the exhaust product is water, and you can make your own fuel. If we understand the energy choices that we will make in the future, hopefully it will reduce anxiety over our energy future and help us to make choices and changes."